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iOS

Posted by Justin Comstock
Justin Comstock
101 Points

It seems cumbersome to have to list out each and every enum case like in the video.

Is there a better way to get the cases in the array.

https://teamtreehouse.com/library/concrete-types-and-property-lists-2

2 Answers

Michael Hulet
Michael Hulet
47,913 Points
Michael Hulet
Michael Hulet
47,913 Points

When this video was recorded, that was the only way. You're right that this is super cumbersome and not very DRY. However, in Swift 4.2 (which came out in October, alongside iOS 12 and Xcode 10), the compiler can synthesize conformance to a new protocol called CaseIterable. By marking your enum as conforming to CaseIterable, it automatically gets a static property called allCases, which is an array containing all the cases in your enum. You can mark your conformance like this:

enum VendingSelection: CaseIterable { // Notice the conformance up here
    case soda
    case dietSoda
    case chips
    case cookie
    case sandwich
    case wrap
    case candyBar
    case popTart
    case water
    case fruitJuice
    case sportsDrink
    case gum
}

Later on when you need all the cases in the enum, you can get it like this:

let selection = VendingSelection.allCases
Justin Comstock
Justin Comstock
101 Points
Justin Comstock
Justin Comstock
101 Points

Thanks, I found it out when I asked but I put it inside an array by accident so it didn't work. "[VendingSelection.allCases]" was wrong.